Pulling cable

[Neil Bush]

I need to add a length of coax to an existing feed. I have done this a few times before, but I just wondered... is there a 'best/preferred' way of connecting a pull-cord to the cable?

Neil

[Adrian C]

I don't know preferred, and depends on what space you are pulling through, but I get away with using 2-inch shiney brown polypropylene box packing tape, wrapping first the thinner diameter cable/cord and then overwrapping the other placed side by side. I used to use knots but found them more likely to get stuck in a void somewhere.

[Neil Bush]

Ah, thanks for that, I see what you mean. I haven't ventured up there yet, but I do expect it to be a snug fit, as there is already cable using that route.

[Andrew Mawson]

I use 6mm diam polypropylene rope, and thread the wire in and out of the rope strands a few times, making off the lead and tail with gaffer tape. This way the more you pull, the tighter the wire is gripped.

AWEM

[Dave Liquorice]

I just lay the two side by side and tape over. Forming some sort of ramp over the bit that sticks out on the forward direction.

The big boys (telephone/power etc) pull cables through ducts with a large "finger trap" threaded several feet onto the end of the cable.

you'd need something fairly "dead" rather than "springy" to make one. A length of coax braided screen would work but probably not very many times as copper isn't very strong.

[Bill Wright]

I usually use another piece of coax. The thing is to make sure that the joint is a smaller diameter than the cables, and that it has no edges or protuberances that might snag.

So: Carefully strip back about three inches of outer sheath. Preserve the braid by either unravelling it or pushing it back over the sheath. Cut the dielectric off without nicking the inner. Pull the braid back over the inner. Do this for both cables, the puller and the pulled. Tie a reef knot in the two lengths of braid/inner, but make sure the knot is fairly close to the remaining plastic on both cables, otherwise the joint is too flexible near the knot and can snag on a corner. Wrap the joint with pvc tape, overlapping the plastic just once, pulling the tape tight, adding rigidity but being careful not to exceed the cable diameter. Make sure the tape bridges any protuberances.

Make sure someone feeds the cable as you pull, because otherwise it's more likely to snag.

If it snags pull it back a yard then twist the pulling end one turn and try again.

That's how I do it.

Bill

[Java Jive]

[John Rumm]

You can get commercial versions of those to go on the end of cable rods and fish tapes:

[John Rumm]

Nice description... do you mind if I pilfer that and slap it on the end of the cable pulling section in our wiki. Seems like it would fit nicely here:

[Steve Thackery]

If it's a really tight fit, it's sometimes easier to pull out the existing cable and pull in two new ones, rather than dragging the new cable past the old one. Mind you, this is mainly relevant to ducted cables. It's a trick I learned when I worked in BT.

[dennis]

For coax I strip about 60 mm back to the centre conductor and make a loop to tie the string to. Then a wrap of tape to smooth it out.

[Stephen H]

Another trick is to use water based lubricant.

If you want the pukka stuff and are prepared to pay for it, IIRC, its hellerine.

If you're too tight to buy the pukka stuff, then theres KY jelly.....

Regards,

Stephen.

[Colin Stamp]

Hang on. I'm having a thick moment. Once you've got your pulling cable into place, surely you could skip the rest of the procedure!

Cheers,

Colin.

[Graham.]

But don't expect the counter assistant in Boots to believe why you need it.

[David WE Roberts]

I had much the same thought - this run is a bit tight to feed my coax through. No worries, feed some coax through for a puller.......

I assume the method is for pulling a long cable through one or more shorter runs?

[Robin]

Or replacing cable - as for example when using the ancient, water-filled, thin, brown stuff to pull through the wonderful new foam-filled CT100 (though the new stuff being that bit bigger did give rise to a few potential brown pants moments).

[Robin]

Or replacing cable - as for example when using the ancient, water-filled, thin, brown stuff to pull through the wonderful new foam-filled CT100 (though the new stuff being that bit bigger did give rise to a few potential brown pants moments).

[Bill Wright]

I would be honoured.

Bill

[Colin Stamp]

Yep. I admit, the thought of someone struggling to work a length of co-ax into an awkward duct, only to use it to pull in another bit of co-ax brought out the facetious git in me :o)

I guess Bill does that kind of thing a lot and to be fair, it does apply to the OPs situation.

Cheers,

Colin.

[Bill Wright]

My description assumes for simplicity that we are either replacing an old coax, or have had an opportunity to put a (coax) draw wire in during construction.

There's also that situation where it's possible to shove a cable through, but from the wrong direction. To avoid joints you would want to pull the new one through to replace the temporary one that enters from the wrong end.

The method I described can be used to pull two coaxes through using one as a draw wire, as long as the duct is plenty big enough. In extremis it's sometimes necessary to use a working cable as a draw wire for two others, one of which replaces the draw wire.

Bill